GetMeOuttaThisMess Posted October 20, 2017 Share Posted October 20, 2017 Seeing folks here in N. Texas already claiming to be victims of the almighty flu, or know those who allegedly are. Here’s the almighty question. If you do a RFT and it’s positive, yet flu is not reported as active in your area, how much validity do you give the positive test? Yes, someone in our office is doing RFT and it ain’t me. I’ve had a couple (2) that look like they could have it and meet CDC criteria for ILI yet the test validity (PPV) is dependent on it being “active” in the community. Thus the RFT on the same patient with the same sx. is less valid in the summer compared to the winter. Discuss... Link to comment Share on other sites More sharing options...
Guest ral Posted October 21, 2017 Share Posted October 21, 2017 1 hour ago, GetMeOuttaThisMess said: ...someone in our office is doing RFT and it ain't me... Well, it certainly isn't me. ;). LMAO Link to comment Share on other sites More sharing options...
GetMeOuttaThisMess Posted October 28, 2017 Author Share Posted October 28, 2017 Ah, but you just never know... I brought a printout from the CDC regarding the statistical validity of RFT depending on season and the strain of flu being screened for to our monthly meeting. Bottom line, you have to know what the flu situation is in your area from the weekly state health department reports. All that being said, the individual in question went right back to ordering more tests and believing that a "positive" result was from on high and written in stone. Great, subtle comment from the SP to this individual that apparently went over their head during our discussion, "I use tests to confirm my diagnosis, not to MAKE my diagnosis". It must be the codger in me, but if one can't understand the statistical information regarding the validity of tests, how do you know how to INTERPRET the test? Link to comment Share on other sites More sharing options...
Moderator EMEDPA Posted November 1, 2017 Moderator Share Posted November 1, 2017 I only order the test if I would treat a +, and that is pretty rare.... Link to comment Share on other sites More sharing options...
MCHAD Posted November 1, 2017 Share Posted November 1, 2017 Honestly at this point other than being helpful for epidemiological purposes what good does it do to know for sure someone has the flu...tamiflu is worthless so all we have to offer is supportive care anyways! Link to comment Share on other sites More sharing options...
GetMeOuttaThisMess Posted November 1, 2017 Author Share Posted November 1, 2017 10 hours ago, MCHAD said: Honestly at this point other than being helpful for epidemiological purposes what good does it do to know for sure someone has the flu...tamiflu is worthless so all we have to offer is supportive care anyways! Simply because people LOVE tests and believe that the results are engraved in stone. I did one yesterday on a young child with a reported fever of 104 (tympanic, so you almost lose all validity with me there) who was afebrile on presentation (imagine that) w/o any other sx. including cough or sore throat (definition per CDC of ILI). Why did I do the test? A 4 m/o sibling was on the floor in a carseat carrier. As I explained to mom, the test wasn't necessarily for the benefit of the pt. but rather for the infant. Test was negative. With our rapid tests, A sensitivity is 90%, B sensitivity is only 70%. To make matters worse, the reported ILI activity in the state is at <2.5% which really bottoms out the PPV of the test to begin with (most positives are false-positives in other words). Me personally, if I have someone at high risk (see CDC criteria) then I'll do one not so much because medication makes a difference but because it is the "standard of care" in my community and I'll tell them to prepare to drop >$100 for benefit which equals treating strep throat (drops a 1/2 day off illness duration and may lessen severity of sx.). The one thing that I DO warn everyone about, whether it is today's head/chest cold or influenza, is to focus on the chest since that's the area that most folks will get into serious trouble (secondary pneumonia). Link to comment Share on other sites More sharing options...
UpRegulated Posted November 7, 2017 Share Posted November 7, 2017 On 10/20/2017 at 5:46 PM, GetMeOuttaThisMess said: Seeing folks here in N. Texas already claiming to be victims of the almighty flu, or know those who allegedly are. Here’s the almighty question. If you do a RFT and it’s positive, yet flu is not reported as active in your area, how much validity do you give the positive test? Yes, someone in our office is doing RFT and it ain’t me. I’ve had a couple (2) that look like they could have it and meet CDC criteria for ILI yet the test validity (PPV) is dependent on it being “active” in the community. Thus the RFT on the same patient with the same sx. is less valid in the summer compared to the winter. Discuss... The studies are based on predefined criteria, the patient is not. These studies are based on CDC criteria of ILI, but that in and of itself does not mean the patient does or does not have influenza. So...treat the patient not the test? Not being sarcastic at all, just that it's easy to tie onself in knots over a positive or a negative result of whatever POC test. I remind myself from time to time that there was a day when there were not rapid flu tests, rapid streps, POC mono's, etc. It forces me to rely more on my history, exam and clinical judgement. There are numerous studies on multiple POC labs, which are helpful, but there seems to be a lot of inter-manufacturer variability. Unfortunately, for example, my facility uses a rapid strep that I put zero faith in. We almost never get a positive, but when we do, it is inevitably in someone that doesn't even have a sore throat, or an intermittent sore throat at best (our MA's and nurses swab "sore throat" complaints before I see them most of the time). At the same time, many of the POC tests we do are for self-limiting illnesses. So I'm kinda "meh" on POC tests for acute illness. I use them as part of my clinical decision making, but certainly not the crux of it. Link to comment Share on other sites More sharing options...
GetMeOuttaThisMess Posted November 7, 2017 Author Share Posted November 7, 2017 My point was why do the test if the validity of the study is not reliable? The CDC criteria for ILI has no bearing on the test validity. The validity is based on the prevalence of the disease in the community. That is why a positive in July is less reliable than one in January. Maybe I’m just one of the nerds that likes to look at statistical validity in the tests that I do. When the sensitivity of Centor is greater than that of our RST in adults I think we have an issue with doing a test for the sake of doing a test. Link to comment Share on other sites More sharing options...
Guest UVAPAC Posted November 7, 2017 Share Posted November 7, 2017 There is a good algorithm in the CDC Guidance: https://www.cdc.gov/flu/pdf/professionals/diagnosis/clinician_guidance_ridt.pdf I interpret the above as: During peak flu season it is not necessary to perform a rapid flu test, as it can be presumed one has influenza based on their subjective/objective examination. (Whether or not you believe in prescribing anti-virals is another story). During off-season, if a patient has subjective/objective flu symptoms (and has co-morbidities) and you would consider anti-virals if they indeed had the flu, a rapid-flu test can be used to assist in making that determination despite the supposed decreased validity of the test. Sadly in today's world patient's like tests/diagnosis and therefore I will typically order a rapid flu test on the majority of patients who fit the criteria. It is extremely rare I prescribe Tamiflu, but agree with CDC if significant co-morbidities I figure why not... Link to comment Share on other sites More sharing options...
UpRegulated Posted November 7, 2017 Share Posted November 7, 2017 1 hour ago, GetMeOuttaThisMess said: My point was why do the test if the validity of the study is not reliable? The CDC criteria for ILI has no bearing on the test validity. The validity is based on the prevalence of the disease in the community. That is why a positive in July is less reliable than one in January. Maybe I’m just one of the nerds that likes to look at statistical validity in the tests that I do. When the sensitivity of Centor is greater than that of our RST in adults I think we have an issue with doing a test for the sake of doing a test. That's kind of my point too. But any test based on the prevalence of a disease in the community relies on some other measure/test to measure/test the prevalence of a disease in a community. I too am the nerd that likes to look at the statistical validity of a given test, but that only has so much utility in a real-world clinical setting. My point being that we can get too wrapped up in the stats/"research" of POC tests. To me, they are on a practical level just part of the history. Flu + or -, Tamiflu or other antivirals do practically nothing. Combine that with the fact that I have little trust for POC tests given the inter-manufacturer lack of reliability, I fall back on clinical judgement, which is probably what we should be doing anyway. I agree with you on Centor, BTW. I rely more on Centor criteria than rapid streps at my facility, to the point I note "Centor criteria +" in my charts when I treat. And Centor is based on history and exam, not a POC test. Let me add that even the "perfect" POC test relies heavily on the ability of the person administering it, as do all diagnostics. There are too many MA's and nurses that can't adequately swab tonsils or a nasopharynx for us, as providers, to not take the results with a grain of salt. So you are right, why do POC tests at all? I'd be cool with not doing them to be honest with you, to a certain degree. But I order them to have a little more data along with my history and physical. I use them as part of my MDM, just as one would do with any lab test. But no test, POC or not, makes or breaks a diagnosis. It is sometimes too easy for providers to exclusively use diagnostics to rule in or out. Diagnostics tests are great and essential to good practice, some are so good as to offer "gold standards" for diagnosis, but we as providers need to understand the utility of one diagnostic test vs. another. POC RI/URI tests suck. Flu test included. Link to comment Share on other sites More sharing options...
GetMeOuttaThisMess Posted November 7, 2017 Author Share Posted November 7, 2017 Two statements that I give thought to, 1) why do the test if it won’t change your treatment plan, and 2) use the test to confirm a diagnosis (I throw in the addition of only do so if you consider the result somewhat valid), not to make one. If someone is doing these tests just to make the diagnosis then I suspect the clinical acumen, or decision making ability is somewhat lacking. Case in point, I don’t even bother to look at the UA result before talking to a sx UTI pt. Why? Hx is 85% sensitive and UA is only 65% sensitive. Why is UA so low? You can easily explain away a positive UA finding to something else. Link to comment Share on other sites More sharing options...
UpRegulated Posted November 7, 2017 Share Posted November 7, 2017 18 minutes ago, GetMeOuttaThisMess said: Two statements that I give thought to, 1) why do the test if it won’t change your treatment plan, and 2) use the test to confirm a diagnosis (I throw in the addition of only do so if you consider the result somewhat valid), not to make one. Not sure if you are replying to me or not, but good point. A POC test should be part of the data like ROS, PE. When an older adult presents with FUO, with only body aches, chills, malaise and fatigue with a clear UA and a + flu, you have a reasonable idea of what is going on. Or at least a reasonable management approach. Hx is 90% of your diagnosis. PE and labs are to help confirm, so long as limitations are understood. Link to comment Share on other sites More sharing options...
Moderator ventana Posted November 7, 2017 Moderator Share Posted November 7, 2017 On 11/1/2017 at 9:55 AM, GetMeOuttaThisMess said: Simply because people LOVE tests and believe that the results are engraved in stone. I did one yesterday on a young child with a reported fever of 104 (tympanic, so you almost lose all validity with me there) who was afebrile on presentation (imagine that) w/o any other sx. including cough or sore throat (definition per CDC of ILI). Why did I do the test? A 4 m/o sibling was on the floor in a carseat carrier. As I explained to mom, the test wasn't necessarily for the benefit of the pt. but rather for the infant. Test was negative. With our rapid tests, A sensitivity is 90%, B sensitivity is only 70%. To make matters worse, the reported ILI activity in the state is at <2.5% which really bottoms out the PPV of the test to begin with (most positives are false-positives in other words) Ugh,,, I just about blew out my coffee through my nose..... really, you tested a kid you knew you did not have the flu, with a test that runs 70-90% sens/spec Insert sound of me smaking my own forehead.... Wife recently brought my kid to peds office (saw newer provider)- gi issue - chronic, little bit of night time "tummy ache" about 40 tests later, nada.... then I get the bill for the testing.... and almost fell over - no way I would have gone so far overboard on testing and it was EXPENSIVE. I truly think they did not know what to do so they just ordered everything.... and I am left to pay for it..... From a very simple perspective, if you knew the kid did not have the flu(remember the test CONFIRMS the clinical Dx) - the only positive you would get would be a false positive - then you are stuck...... do you give tamiflu and give people GI upset, drain their wallets, and not help. Or not give them tamiflu and be labeled a bad provider?? I actually stop testing once CDC says it is in the area, (they lag behind) or I see it in the area.... whats the point?? Link to comment Share on other sites More sharing options...
GetMeOuttaThisMess Posted November 7, 2017 Author Share Posted November 7, 2017 2 hours ago, ventana said: Ugh,,, I just about blew out my coffee through my nose..... really, you tested a kid you knew you did not have the flu, with a test that runs 70-90% sens/spec Insert sound of me smaking my own forehead.... Wife recently brought my kid to peds office (saw newer provider)- gi issue - chronic, little bit of night time "tummy ache" about 40 tests later, nada.... then I get the bill for the testing.... and almost fell over - no way I would have gone so far overboard on testing and it was EXPENSIVE. I truly think they did not know what to do so they just ordered everything.... and I am left to pay for it..... From a very simple perspective, if you knew the kid did not have the flu(remember the test CONFIRMS the clinical Dx) - the only positive you would get would be a false positive - then you are stuck...... do you give tamiflu and give people GI upset, drain their wallets, and not help. Or not give them tamiflu and be labeled a bad provider?? I actually stop testing once CDC says it is in the area, (they lag behind) or I see it in the area.... whats the point?? No charges to clientele for tests. Documented febrile illness w/o focal source in child w/ sibling not eligible for vaccination for flu based on age. If test had been positive, yes, I would’ve had mom contact her peds for treatment recommendation since we don’t see clientele of that age (baby in carrier). In this particular case I DIDN’T know that older kid (male) couldn’t possibly have it due to nature of temp elevation (note degree of elevation and nature of measurement however). As others have noted, test should be for high risk patients, of which there was one on the floor, based on age and exposure to the one whom I was seeing. I concur with not testing once it’s clearly in the community, which it isn’t as of yet. The point being made is folks have a positive result and assume that the diagnosis is written in stone, whereas the data should lead one to still consider other possibilities. BTW, you should be glad that I didn't have my strawberry toaster strudel in nose to blow back. I am sorry about the personal expense that you incurred with your family testing but that isn't how I roll. I maybe test, aside from UA's, 5-10/year for strep/flu for the reasons mentioned about. Majority of tests are to appease the pt./family. Link to comment Share on other sites More sharing options...
GetMeOuttaThisMess Posted November 7, 2017 Author Share Posted November 7, 2017 10 hours ago, UpRegulated said: Not sure if you are replying to me or not, but good point. A POC test should be part of the data like ROS, PE. When an older adult presents with FUO, with only body aches, chills, malaise and fatigue with a clear UA and a + flu, you have a reasonable idea of what is going on. Or at least a reasonable management approach. Hx is 90% of your diagnosis. PE and labs are to help confirm, so long as limitations are understood. Nah, it was just a general statement. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.